Oxygen rise in the tropical upper ocean during the Paleocene-Eocene Thermal Maximum. (https://pubmed.ncbi.nlm.nih.gov/38359106/)

These scientists were studying what happens to the oxygen in the ocean when the Earth gets warmer. They were particularly interested in a time called the Paleocene-Eocene Thermal Maximum (PETM), which was a period of extreme warming on Earth a long time ago.

To understand what was happening with the oxygen in the ocean during this warm period, the scientists looked at tiny creatures called foraminifera that lived in the ocean. These foraminifera hold clues about the oxygen levels in the water.

What the scientists found was that during the PETM, the tropical North Pacific Ocean actually had more oxygen than before. This was surprising because they expected the oxygen levels to decrease due to the warming of the Earth.

The scientists think that the increase in oxygen in the tropical North Pacific Ocean during the PETM might have helped prevent a mass extinction of marine life. They used computer simulations to show that when the Earth gets warmer, the decrease in biological activity in the ocean can actually lead to more oxygen in certain parts of the ocean.

Overall, this study showed that even though global warming can decrease the overall oxygen levels in the ocean, there are some complex ways in which oxygen levels can change in different parts of the ocean during periods of extreme warming.

Moretti S., Auderset A., Deutsch C., Schmitz R., Gerber L., Thomas E., Luciani V., Petrizzo MR., Schiebel R., Tripati A., Sexton P., Norris R., D'Onofrio R., Zachos J., Sigman DM., Haug GH., Martinez-Garcia A. Oxygen rise in the tropical upper ocean during the Paleocene-Eocene Thermal Maximum. Science. 2024 Feb 16;383(6684):727-731. doi: 10.1126/science.adh4893. Epub 2024 Feb 15.